[1] the top testimonial on https://jj-vcs.github.io/jj/latest/testimonials/ is mine
(The first was BitKeeper, which also was a tremendous achievement.)
> In February 2000, they contacted Karl Fogel, the author of Open Source Development with CVS (Coriolis, 1999), and asked if he'd like to work on this new project. Coincidentally, at the time Karl was already discussing a design for a new version control system with his friend Jim Blandy. In 1995, the two had started Cyclic Software, a company providing CVS support contracts, and although they later sold the business, they still used CVS every day at their jobs
You may recognize Jim as one of the authors of Programming Rust.
- deferred conflict resolution
- The very expressive revset language
- the op log and ability to undo any operation
Many things that you can do with the git cli are significantly easier and in some cases comparatively effortless using jj. If all you do is git add and git commit then you probably aren't missing out on much, but if you ever split or rebase commits you should definitely try jj.